1. Field of the Invention
This invention relates to on-site loose fill packaging systems and, more particularly, to a) a valve for controllably delivering discrete loose fill particles from a supply to a packaging site; and b) a fluid valve operatively connected to the loose fill valve for selectively directing an additive/adhesive through a nozzle onto the conveying loose fill particles with the loose fill valve open and, on demand, a flushing fluid through the nozzle with the loose fill valve closed.
2. Background of the Invention
Packaging of articles for safe shipping and handling is a critical part of virtually all businesses that deal in fragile goods. Those in the packaging industry strive to achieve two, oft times competing, objectives--that of producing low cost packaging that is effective in minimizing breakage/damage of product. Packaging costs become highly critical for goods with low profit margin. As a result, over the years, the packaging industry has become increasingly competitive.
There are presently three primary methods of packaging fragile items--"foam in place", "loose fill" and custom fabricated foam shape packaging. The foam in place technique employs two reactive chemicals which are measured and interacted to instantly produce a low density packaging foam. The foam is directed into article-carrying containers on-site and expands within the constraints of a container to surround, and thereby provide a cushion for, articles within the container.
There are many drawbacks with this packaging technique. The chemical reactants are hazardous. Care must be exercised to protect the system operators. Proper ventilation is recommended in plants and often requires modification to existing systems. Because the polymerization is taking place on-site, the reaction gases, even when vented, tend to pollute the plant environment. Discharge of waste chemical components, and containers therefor, must also be contended with. Further, foam in place packaging cannot be practiced with articles that are heat sensitive because the reaction of components is exothermic. A further drawback with foam in place systems is that the environment therearound is very difficult to keep clean. A still further problem with foam in place systems is that the equipment for processing the same is relatively complicated and requires periodic maintenance. Poorly maintained metering and mixing equipment may produce improper component ratios which minimizes yield and compromises the integrity of the foam end product.
While the foam in place industry has thriven, the above problems have been contended with. The adhesive coated loose fill packaging technique obviates many of the above problems and is, in many applications, a preferred alternative to foam in place.
To produce loose fill, resin material is expanded, in bulk by converters worldwide. The resulting expanded polystyrene particles, referred to commonly in the industry as "peanuts", are shipped in bulk from the converters to individual customers.
Loose fill packaging operations typically gravity feed the discrete loose fill particles into a container for an article to be shipped. At customers' facilities, the peanuts are stored in bulk supply hoppers and normally fed through a depending, flexible conduit which is controlled by the operator to direct a desired amount of the loose fill into a container in which an article is to be shipped. It is known in the art to discharge loose fill into the bottom of an empty container, place an article to be shipped thereover and then cover the article with a further supply of the loose fill.
Product migration within the loose fill is a problem. This is caused by vibrational settling of the product in the carton due to the continued package vibration encountered in the shipping environment. Also, damage caused by abrupt movement or impact to the package is costly to the shipper.
To improve the loose fill cushioning potential and prevent this migration, The Dow Chemical Company devised a method of coating the particles with an additive/adhesive that bonds the particles to each other to effectively produce, once the additive cures, a solid cushioning block of loose fill particles. The packaging method and additive/adhesive invented by The Dow Chemical Company are described fully in U.S. Pat. Nos. 4,588,638 and 4,644,733, both issued in the name of Dolinar, and assigned to The Dow Chemical Company.
The Dow Chemical Company also has a loose fill dispensing control valve and additive applicator system which it currently markets under its trademark PELASPAN MOLD-A-PAC.RTM.. The Dow Chemical Company has been the leader in the loose fill industry and its equipment is considered to be representative of the state of the art. The following is a brief description of The Dow Chemical Company's equipment that is currently being used in the industry.
The prior art structure is a fixed, self-contained unit which must be suspended from a rigid, overhead support. The unit employs a master, electromechanical control which operates mechanically independent valves for controlling a) the delivery of loose fill particles through the conduit; and b) the delivery of additive/adhesive and flushing fluid/water through a discharge nozzle within the conduit. The control system is very sophisticated, with coordinated operation of the fluid and loose fill valving.
Sophisticated electromechanical equipment has inherent drawbacks. The manufacturing costs therefor are relatively high. A skilled technician is required to install the unit and make on-site repairs thereto. Failure of any part of the equipment may render an entire system unuseable. The resulting down time may be devastating to the operation of a business.
A further drawback with the prior art system is that the conduit, which guides the loose fill from a loose fill supply hopper into a container, is rigid between the point of connection with the hopper and the discharge end of the conduit. To control the discharge of loose fill into a container, the operator must manipulate the container, not the conduit. In some cases, the size and weight of the container may make this impractical. The inconvenience is apparent.
Further, because the outlet end of the conduit is fixed, the container size is limited by the dimension between the outlet end of the conduit and the conveyor, which advances the containers into a filling position beneath the conduit. As the container height varies, the distance between the outlet end of the conduit and the container opening likewise varies, which is undesirable. Preferably, the discharge end of the conduit is in close proximity to the top opening in the container. However, because the vertical spacing between the conveyor and outlet end of the conduit is generally chosen to accommodate the largest anticipated container size, an undesirably large distance is created between the discharge end of the conduit and the top opening in small containers, which makes difficult the introduction of the loose fill thereinto. The result may be a significant amount of the loose fill falling onto the conveyor and surrounding work area, necessitating ongoing cleanup.
A further drawback with the prior art systems is that the loose fill blocking surface in the conduit is considerably above the location of the nozzles which apply additive to the conveying loose fill material. Accordingly, the metal housing which incorporates both the blocking surface and delivery nozzles must have a large vertical dimension, which results in a large and heavy structure.
A further drawback with the electromechanically controlled systems is that, in the event of a power failure, the entire system is disabled.